Intro: Speaker Cabinet and Art Shelf From Old Car Speakers
Update: Better final pictures
After doing a complete sound system overhaul on my friend's Subaru Imprezza I found myself very impressed with the build quality of the factory speakers. Separate tweeters, woven cone, decent sized magnet, solid basket structure.. I felt like it would be a waste to throw away well built and almost brand new speakers. I told him... give me a little time, I'll re-purpose these into something for you.
I had seen instructables and commercially available products before that were essentially a single speaker tower like what you would find in a nice home theater but with aux or BT inputs to be stand alone units. My issue with so many of them is that they were either under powered, ugly as all heck, or just didn't look like they could really hold their own. I didn't want to build a speaker box, I wanted to build a piece of furniture that my friend would be proud to display in his home for years to come.
My goal for this project was that it would:
-be visually appealing
-serve a secondary purpose other than playing music
-be easy to use
-not break the bank
Tools I used:
Step 1: Drawing It Up
I took out four 6.5" main drivers and two tweeters so I had those to work with.
As you can see, I'm terrible at drawing. Take a look at the initial idea on a legal pad. Bad.
Enter Google SketchUp. I had never used drawing software before but I knew if I really wanted to plan out a great piece I would need something that could give me dimensions and a good visual representation as I drew. After watching a few tutorials I was proficient for my task.
The first rendering was flat. After a few more videos though I was learning out to pull, push, drag, and my idea was actually starting to take shape! I figured I would put the extra tweeters up top closer to ear level so it wouldn't sound like a boom box set on the floor.
Step 2: Getting Supplies
Before I even stopped at the lumber yard I bought all the electronics that I planned to fit into this thing. After a lot of deliberation I went with the following:
-24VDC power supply
-4 channel amplifier board (4x100 at 4ohms powered by 24V)
-2 small ports (to house the tweeters)
-1 large port
-4 rubber feet
-2 6ft power cords
-2 LED strips (24V version)
My own supplies
-power wire receiver (from an old PC power supply)
-Aluminum L stock
Then I got my lumber, 3/4" Birch, and also the following to finish off my supplies:
Local supply stores
-shallow wall switch box
-shallow switch and cover
-wood stain and poly clear coat
-black enamel paint
Step 3: Start Cutting!
I have to admit, I was very nervous to start cutting. Since this was one of my first major wood working projects I didn't want to mess up too many cuts and go over my budget having to buy more plywood or worse, blades and bits. I had the help of a friend for the first few rips on the table saw. It's pretty hard to wield a 4x8 sheet of ply through a saw by yourself, I wouldn't suggest trying. I did simple cuts that were the width of the sides and then the width of the unit from straight on, knowing I could bring the length down later by myself.
The saying is, "Measure twice, cut once". For me it was, "measure like 14 times, cut once, maybe twice if you flub it"
I also bought myself a nice compass, some pencils and started off with the more detailed cuts. The great thing about using SketchUp is that I could just ask it for dimensions and there they were. The only other math I did was figuring out widths of the horizontal pieces since they would be recessed after using a dado joint (a slot or trench cut into the surface of a piece of material, usually wood). One of my test dado joints is seen below.
Not a ton of pictures here, but I cut all my flat pieces first, then went over everything with the router that needed the dado joint, then went back to the flat pieces and cut speaker and port holes.
I made some pretty big mistakes with the router. It was borrowed and I needed to get it back to the owner quickly. Long story short I had to use almost the entire tube of wood filler that I bought. Food for thought, when you will have two sides of a box and the grooves are not symmetrical front to back you must account for the fact that one will mirror the other, not look the exact same...
Step 4: Test Fit, Then Add Some Glue
Once all the wood was cut I needed to test fit it all before gluing. Believe it or not but in these photos I was just careful to stand it up with pressure on the outside and the strength of the joints kept it all together!
Once I was happy with how things were fitting together I took it all back apart and started gluing pieces in. I put all the pieces into one side, then last I applied glue to all my joints on the other side and worked it onto the rest of the piece.
I had very limited resources when it came to wood clamps. I used what I had and then simply stacked a bunch of very heavy items on top of what was left. I used a piece of scrap wood on top of the unit to protect it from scratches. I would definitely suggest getting more clamps next time...
Step 5: Add the Components
Once all the glue was set I stood her up and started doing the wiring.
On the back I put the power supply and amplifier low to keep it from getting too top heavy. All the power and speaker connections are soldered or screwed tightly depending on the placement.
The power supply I mounted off the baffle a small amount to allow air to come in through the vents and out through the fan. Power is controlled with a simple light switch up top. The alternative was to switch the power going to the amp with its on-board circuits, but that would mean the power supply was running all the time, and I didn't like that idea. Instead the power comes in through a 2x4 with the PC power supply connector, then up and through the switch before returning to the power supply. Power then runs up to the amp and also the LED strips which are placed at the top of the shelf area. I didn't want to do the typical green power LED as this would take away from the aesthetic nature of the piece. The strips turn on with the switch. This way you know when the unit is on and you remember to shut it down before the end of the night. The amp, due to its design, is not equipped to modulate volume. The only volume adjustment then is on the device sending signal to it through the 1/8" minijack cable(not pictured). This keeps with my idea for wanting to make it simple.
Instead of doing individual speaker grills as originally intended I decided to clean up the look and just make main speaker grills with some speaker grill cloth I had on hand. I used some 1/2" MDF and cut out holes big enough to fit around the speaker assembly.
I also took some measurements and cut a piece of Masonite to cover the back. The power supply has a fan so I'm not worried about the amp getting too hot during use. I added another hole in the 2x4 to allow air to be pulled through as well.
Step 6: Make It Pretty
I was able to test out my stain color on another piece I was working on for a friend, a Pinterest pallet wine rack.
In order the pictures are:
Starting to stain
One coat finished
Two coats finished
Shelf finished with test fit of grills
Just needs a quick sand, poly application, and it's all set!
I must say that in the pictures I think it looks better with just one coat where you can still see some of the grain. We'll see what happens after the sand and poly.
Step 7: Final Product
After a little sanding and some poly this thing looks fantastic. I'm at just over $300 in parts on this project and a TON of hours, but I'm happy with the result. Sadly it will be going to live with my friend now but it's been an excellent learning experience.
Aside: I wanted some sign that this all was inspired from a set of car speakers so I bought a Subaru emblem. It had double sided tape on the back up of it but I wanted it to be removable in case my friend decided against it. To do this I cut a small piece of flat steel stock and stuck it to the tape. Then I put duct tape over the steel so it wouldn't snag the speaker cloth. Next I took the grill off and drilled a 1/2" hole almost all the way through it from the back. Finally I placed inside that hole a small neodymium magnet. It's strong enough to hold the emblem in place via the steel on the back, but easy enough to remove. It was actually an idea I had thought I would use for the speaker grills themselves but decided instead to go with a pressure fit from the surrounding wooden structure.
Sorry for the poor quality photos.
Hope you enjoyed reading about this!